I have VPLS fully functional using Cisco Route Reflectors on MPLS. However I cannot figure out how to tunnel VLANs through the VPLS from one Tik to another. I am pretty sure the problem is the L2MTU on a VLAN attached to the bridge of a VPLS gets set to 1496. However I cannot figure out how to get the Tik to let me adjust the L2MTU of the Cisco BGP VPLS. Has anyone else run into this? How have you fixed it?
I have confirmed its L2MTU. The L2MTU of the bridge gets changed form 1508 to 1500, thereby changing any VLANs attached to the bridge to 1496.
Anyone know what the solution is to resolve this?
Well, according to some other thread I recently read here, Mikrotik’s official response is that you can’t.
If you need this, you will have to open a ticket asking for this particular feature.
Cisco uses a 1 byte prefix length field. Mikrotik uses a 2 byte prefix length field. I couldn’t find a way to get Mikrotik to use 1 byte. But the Cisco has a config for clients uses a 2 byte prefix length field:
router bgp 65000
address-family l2vpn vpls
neighbor x.x.x.x prefix-length-size 2
And now I can configure standard BGP VPLS interfaces on the mikrotik with a custom L2MTU while using a Cisco Router Reflector.
Interesting, which ROS version are you using? According to mrz, this shouldn’t work:
http://forum.mikrotik.com/t/increasing-vpls-advertised-l2-mtu/78269/2